Article
Chemistry, Physical
Patrycja Olczyk, Andrzej Sikorski
Summary: The structure of very thin polymer films formed by strongly adsorbed macromolecules was investigated using computer simulation. A coarse-grained model of strictly two-dimensional polymer systems was constructed and its properties were determined through efficient Monte Carlo simulations. The effects of temperature, chain length, and polymer concentration on the macromolecular structure were examined, showing that the chain size increases with concentration at low temperatures while decreasing at high temperatures, indicating the influence of inter-chain interactions.
Article
Polymer Science
Katsumi Hagita, Takahiro Murashima, Hiroshi Jinnai
Summary: This study investigates the qualitative behavior of large rings embedded in crosslinked polymer networks through coarse-grained molecular dynamics simulation. The results show that the large rings interfere with the network structure and have an impact on the stress-strain curve. The study also confirms that these embedded rings can act as movable crosslinks and reinforce the network.
Article
Polymer Science
Yuya Doi, Atsushi Takano, Yoshiaki Takahashi, Yushu Matsushita
Summary: The study found that dumbbell polymers form a unique network structure with distinctive entanglement characteristics in the system. Dumbbell PS samples with longer central chains exhibit slower terminal relaxation and retain entanglement features in high-concentration DOP solutions.
Article
Forestry
Zepeng Mei, Keyan Fang, Qichao Yao, Zhou Wang, Maosheng He, Hao Wu, Feifei Zhou, Wanru Tang, Maowei Bai, Zhipeng Dong
Summary: Tree-ring fire scar is a crucial proxy for reconstructing historical wildfires. However, accurately determining the year of fire occurrence has been challenging. In this study, a novel approach using abrupt shifts in tree-ring geometric center is proposed to detect fire occurrence years. The method has been validated and shown to accurately identify the exact year of fire occurrence.
Review
Forestry
Tongwen Zhang, Jinghui Song, Yuting Fan, Yan Liu, Shulong Yu, Dong Guo, Tianhao Hou, Kailong Guo
Summary: This paper compiles and analyzes the literature on vegetation index research based on tree-ring information in the past 20 years. It provides an overview of the relationship between tree-ring parameters and NDVI, as well as NDVI reconstruction. The research shows a strong correlation between tree-ring parameters and NDVI in summer. In addition, combining tree rings with NDVI is useful for assessing forest decline, quantifying the forest response to drought, and monitoring forest productivity. Future research should consider multiple environmental factors and conduct large-scale studies on the climate response of forest tree growth and the reconstruction of historical vegetation index sequences.
Article
Physics, Condensed Matter
Jalim Singh, Prasanth P. Jose
Summary: Molecular dynamics simulations on model linear polymers reveal violations of Stokes-Einstein relation in monomer density relaxation across different densities, with a weak violation of Stokes-Einstein-Debye relation near the transition temperature in lower density systems. Additionally, jumplike motions are observed in typical monomer trajectories, contributing to the violations, along with a decoupling of translational and rotational dynamics in the polymer system.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Review
Polymer Science
Jordan Ochs, Carlo Andrea Pagnacco, Fabienne Barroso-Bujans
Summary: Cyclic polymers, with their circular structure and lack of chain ends, exhibit unique properties and potential applications. However, the preparation of high-purity cyclic polymers in large quantities remains challenging and requires continuous development of synthetic methods and techniques.
PROGRESS IN POLYMER SCIENCE
(2022)
Article
Polymer Science
Carlo Andrea Massa, Francesco Puosi, Dino Leporini
Summary: Extensive molecular-dynamics simulations were used to study a polymer model exhibiting heterogeneous Johari-Goldstein secondary relaxation. The time-temperature-pressure superposition of the primary relaxation was confirmed. The time scales of the primary and JG relaxations were found to be highly correlated, in agreement with the predictions of the Coupling Model. However, the exponent of the power law deviated from the expected value, potentially due to the specific relaxation process and the heterogeneity of the JG process.
Article
Multidisciplinary Sciences
Malgorzata Jastrzebska
Summary: This paper focuses on the description of rings with a given property of the lattice of left annihilators, pointing out the symmetry between the lattices of left and right annihilators in any ring. It proves the conditions under which the lattice of left annihilators in a unital associative ring is Boolean, and explores the relationship between the lattice of left annihilators being two-sided ideals and complemented. Additionally, it demonstrates that the assumption of the ring being unital is necessary in certain results and provides further insights into rings with distributive or complemented lattices of left annihilators.
Article
Multidisciplinary Sciences
Takahiro Shimojima, Asuka Nakamura, Xiuzhen Yu, Kosuke Karube, Yasujiro Taguchi, Yoshinori Tokura, Kyoko Ishizaka
Summary: The study successfully tracked the dynamics of skyrmions and revealed their evolution at different time scales. The repeatable motion of magnetic skyrmions around defects demonstrates the arrangement and relaxation of skyrmion clusters.
Article
Biodiversity Conservation
Ireneusz Malik, Maciej Dluzewski, Joanna Rotnicka, Malgorzata Wistuba, Kazimierz Krzemien, Andrzej Muszynski, Elzbieta Rojan, Albert Slezak
Summary: The study found that a large flood in 2014 caused silver poplar trees in the semi-arid High Atlas Mountains of Morocco to exhibit dual, opposite growth reactions in the following year, with half of the trees developing wider rings and the other half developing narrower rings. The wide rings were attributed to a sudden supply of water benefitting the trees, while the narrower rings were a result of environmental stress related to sediment deposits from the flood. This demonstrates the importance of considering detailed analysis of individual tree responses to environmental events, rather than relying solely on average ring widths.
ECOLOGICAL INDICATORS
(2021)
Article
Environmental Sciences
Li Fu, Yan Xu, Dan Zhao, Bingfang Wu, Zhihong Xu
Summary: This study aimed to investigate the responses of Pinus tabuliformis, a major coniferous tree species, to air pollution in the Miyun Reservoir Basin (MRB) in Beijing. The results showed an overall increase in intrinsic water-use efficiency (iWUE) of Pinus tabuliformis, and the contribution of atmospheric CO2 concentration (c(a)) to tree growth was significant at remote sites. The study also found that heavy air pollution led to further stomatal closure, as evidenced by higher delta C-13 levels in tree rings.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Polymer Science
Seung Heum Jeong, Soowon Cho, Chunggi Baig
Summary: This study presents a detailed analysis of the scaling behavior of chain rotation dynamics in shear flow for melt and dilute linear polymer systems. The results show that dilute systems with hydrodynamic interaction (HI) and excluded volume (EV) effects exhibit two distinct scaling behaviors of chain rotation time between the intermediate and strong flow regimes. In contrast, free-draining dilute polymer systems display a simpler single-scaling behavior throughout the intermediate-to-strong flow regimes. The combined HI and EV effects weaken the structural change of polymer chains and enhance chain rotation dynamics by disturbing chain stretch and alignment to the flow direction. The presence of intermolecular interactions between chains in melt systems leads to two distinct scaling behaviors of chain rotation time as well. The overall scaling behavior of chain rotation is determined by the kinematically stable angular regions near the flow direction, while the kinematically unstable angular regions exhibit affine chain rotation dynamics. This study provides important insights into the understanding of chain rotation dynamics in shear flow.
Article
Environmental Sciences
Hamid M. Behzad, Yongjun Jiang, Muhammad Arif, Chao Wu, QiuFang He, Haijuan Zhao, Tongru Lv
Summary: The study found that tunnel construction-induced groundwater depletion negatively affects the growth levels of forest trees, particularly in karst landscapes. Trees with faster growth rates show more significant adverse growth levels in response to tunneling or drought-induced water stresses, and exhibit the highest recovered growth levels in favorable climatic conditions, indicating sensitivity to climate conditions.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Mechanics
Benjamin E. E. Dolata, Peter D. D. Olmsted
Summary: We develop a thermodynamically consistent framework to incorporate entanglement dynamics into constitutive equations for flowing polymer melts. Our model combines the convected constraint release (CCR) dynamics with a finitely extensible version of the Rolie-Poly model and includes an anisotropic mobility as in the Giesekus model. The reversible dynamics are described by a free energy that accounts for both a finitely extensible conformation tensor and an ideal gas of entanglements. The dissipative dynamics give rise to coupled kinetic equations for the conformation tensor and entanglements, with coupling terms that capture shear-induced disentanglement. The relaxation dynamics of the conformation tensor follow the GLaMM and Rolie-Poly models, incorporating reptation, retraction, and CCR. Our model proposes a proportional relationship between the relaxation time for entanglement recovery and the Rouse time that governs polymer stretch within the tube. This aligns with recent molecular dynamics simulations and suggests that anisotropies in reptation dynamics may contribute to slow re-entanglement signatures observed in step-strain experiments.
JOURNAL OF RHEOLOGY
(2023)
Biographical-Item
Physics, Multidisciplinary
M. Ya Azbel, A. F. Andreev, B. M. Bolotovskii, A. Yu Grosberg, N. M. Kreines, L. S. Levitov, L. P. Pitaevskii, V. L. Pokrovskii, E. I. Rashba, A. I. Smirnov, D. E. Khmel'nitskii, A. V. Chubukov
Editorial Material
Multidisciplinary Sciences
Alexander Y. Grosberg
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2020)
Article
Multidisciplinary Sciences
Jan Smrek, Iurii Chubak, Christos N. Likos, Kurt Kremer
NATURE COMMUNICATIONS
(2020)
Article
Polymer Science
Angelo Rosa, Jan Smrek, Matthew S. Turner, Davide Michieletto
Article
Chemistry, Physical
Stanard Mebwe Pachong, Iurii Chubak, Kurt Kremer, Jan Smrek
JOURNAL OF CHEMICAL PHYSICS
(2020)
Article
Chemistry, Physical
Iurii Chubak, Christos N. Likos, Jan Smrek
Summary: The study investigates effective interactions in dilute polydisperse ring polymer solutions, deducing the contributions of sterics, topology, and threading for differently sized rings. The research also quantifies the contribution of topological constraints for rings of different asymmetries in length, as well as compares changes in effective potentials when mutual ring threading is restricted. Threading depth distributions at different center-of-mass ring separations are also characterized.
Article
Physics, Multidisciplinary
Kirill E. Polovnikov, Sergei K. Nechaev, Alexander Y. Grosberg
Summary: This study investigates the effect of curved geometry on the conformational statistics of stretched polymers. It reveals that the typical excursions of the polymer away from the surface and the curvature-induced correlation length scale follow power-law relationships, influenced by the Kardar-Parisi-Zhang (KPZ) scaling, and independent of the fractal dimension of the polymer.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Physical
Iraj Eshghi, Alexandra Zidovska, Alexander Y. Y. Grosberg
Summary: In this study, we solve a hydrodynamic model of active chromatin dynamics within a confined geometry resembling the cell nucleus. Analytical and numerical methods are used to describe the behavior of chromatin polymer driven by polar symmetric motors, both in linear response and long-term, fully nonlinear flows. The introduction of a boundary induces a specific geometry in the chromatin flows, which is described using vector spherical harmonics, simplifying the analytical and numerical approaches. Our findings show that the long-term behavior of this model in confinement is characterized by steady, transverse flows of chromatin circulating around the spherical domain, which are robust to perturbations and determined by the size of the domain. This provides further understanding of active chromatin dynamics in the cell nucleus and lays the foundation for the development of more complex models.
EUROPEAN PHYSICAL JOURNAL E
(2023)
Article
Physics, Multidisciplinary
Iraj Eshghi, Alexandra Zidovska, Alexander Y. Grosberg
Summary: This study discovers a new type of nonequilibrium phase transition in chromatin dynamics that explains the observed coherent motions. The cooperation between molecular motors tethered to chromatin drives the flow of solvent past the polymer, influencing the orientation of nearby motors. The predicted length scales match experimental results, providing insights into the effects of activity on the cell nucleus and its contents.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Iraj Eshghi, Alexandra Zidovska, Alexander Y. Grosberg
Summary: This study extends a two-fluid model to investigate the effects of three types of activity (force dipoles) on chromatin and nucleoplasm. The results show that the third type of activity dominates the flow and leads to emergent screening length scales in the system.
Article
Physics, Fluids & Plasmas
Itay Azizi, Alexander Y. Grosberg, Yitzhak Rabin
Summary: A temperature-controlled reentrant transition is observed in simulations of mixtures of small and big particles. The system undergoes a transition from a fluid mixture to a crystal of big particles in a fluid of small particles and then back to a fluid mixture as temperature increases. This solidification is driven by entropy gain of small particles, while melting is caused by enhanced interpenetration of particles at high temperature, reducing the entropic forces that stabilize the crystal.
Article
Chemistry, Physical
Michael Wang, Ketsia Zinga, Alexandra Zidovska, Alexander Y. Grosberg
Summary: The study explores how interactions between components with different levels of activity affect fluctuations of an embedded object, suggesting that hot particles may cause cold particles to accumulate on the surface of the tracer, potentially dampening its fluctuations.
Article
Physics, Multidisciplinary
Alexander Y. Grosberg
Summary: The conjecture proposes that the unknot probability for a randomly generated self-avoiding polygon has only logarithmic corrections to the known exponential law. This conjecture is supported by the numerical result of Baiesi, Orlandini, and Stella in 2010.
Article
Chemistry, Physical
Alexander Y. Grosberg, Yitzhak Rabin
Article
Physics, Fluids & Plasmas
Michael Wang, Alexander Grosberg